Evaluating the Sensitivity and Specificity of Siemens Clinitest Lateral Flow Test and the Simple AMplification-Based Assay (SAMBA)-2 PCR Test for SARS-CoV-2 Infection

Introduction

Accurate point-of-care testing for SARS-CoV-2 could quickly identify which patients need to be isolated and improve flow for patients being admitted as an emergency to the hospital. We evaluated two diagnostic tests with shorter turnaround times, the Siemens Clinitest Lateral Flow (Siemens Healthineers AG, Erlangen, Germany) and the Simple AMplification-Based Assay (SAMBA)-2 PCR test against a standard laboratory PCR test.

Methods

We conducted a prospective diagnostic cohort study in a single English emergency department. Adult participants underwent three swabs: the Siemens Clinitest Lateral Flow Test, the SAMBA-2 and a standard laboratory PCR test.

Results

A total of 212 participants were recruited. The sensitivity and specificity of the Siemens Clinitest Lateral Flow Test against the laboratory PCR test was 55.6% (95% CI 30.8-78.5) and 100% (95% CI 98.1-100) respectively. The sensitivity and specificity of the SAMBA-2 PCR test against the laboratory PCR test was 60.0% (95% CI 32.3-83.7) and 100% (95% CI 97.9-100) respectively.

Conclusion

Neither the Siemens Clinitest Lateral Flow Test nor the SAMBA-2 PCR test demonstrated sufficient sensitivity to rule out active SARS-CoV-2 infection. Both tests demonstrated high specificity.

Combined Point-of-Care Nucleic Acid and Antibody Testing for SARS-CoV-2 following Emergence of D614G Spike Variant

Rapid COVID-19 diagnosis in the hospital is essential, although this is complicated by 30%-50% of nose/throat swabs being negative by SARS-CoV-2 nucleic acid amplification testing (NAAT). Furthermore, the D614G spike mutant dominates the pandemic and it is unclear how serological tests designed to detect anti-spike antibodies perform against this variant. We assess the diagnostic accuracy of combined rapid antibody point of care (POC) and nucleic acid assays for suspected COVID-19 disease due to either wild-type or the D614G spike mutant SARS-CoV-2. The overall detection rate for COVID-19 is 79.2% (95% CI 57.8-92.9) by rapid NAAT alone. The combined point of care antibody test and rapid NAAT is not affected by D614G and results in very high sensitivity for COVID-19 diagnosis with very high specificity.

lepidus Economic benefits of biological control of Sitona obsoletus (clover root weevil) in Southland pasture

Sitona obsoletus is a serious pasture pest in New Zealand where its rootfeeding larvae reduce white clover cover and nitrogen fixation To maintain production farmers may compensate by increasing inputs The parasitic wasp Microctonus aethiopoides Loan was introduced for biological control of S obsoletus and achieved parasitism rates exceeding 70 In Southland where S obsoletus was first detected in 2010 unusually severe and prolonged infestations during 2013 and 2014 prompted intensive biological control releases in 2014 and 2015 This study evaluated if they were cost effective in 2015 On dairy farms biological control returned 1478/ha/year or 23 million over the 158017 ha On sheep and beef farms the estimated return was 686/ha/year or 47 million over 719854 ha Monte Carlo simulations were used to estimate returns (/ha/year) using plausible ranges of model parameter values and returns were positive in at least 975 of simulations Biological control of S obsoletus has returned a net benefit in Southland

The bionomics of an invasive species Sitona lepidus during its establishment in New Zealand

The egg, larval, pupal and adult abundance of the clover root weevil Sitona lepidus Gyllenhal (Coleoptera: Curculionidae) was monitored at three sites for the first ten years following the discovery of this exotic pest in the Waikato region of New Zealand. The species went through an initial boom and bust cycle at two sites, with populations reaching up to 1800 larvae m-2. Thereafter, winter larval populations were relatively stable, ranging between 450-750 m-2. Unlike in the Northern Hemisphere, S. lepidus was found to have two generations a year in the Waikato region of New Zealand. Pasture white clover content at the time of peak adult numbers was positively related to the subsequent peak larval populations for each generation. The factors contributing to the emergence of S. lepidus as one of the most important pasture pests in New Zealand are discussed.

Clover root weevil in the South Island detection response and current distribution

Sitona lepidus had spread throughout the North Island of New Zealand by 2005 and was first detected in the South Island in January 2006 when one individual was found at Harewood Christchurch Intensive sampling during February 2006 recovered only two additional specimens Several specimens were recovered from a separate Christchurch location in August 2006 Localised S lepidus populations were discovered near Richmond Nelson in April 2006 and in Rai Valley in May 2006 A website established in May 2006 to provide information about S lepidus was visited a mean of 135 times per month but it was never used to report possible new South Island infestations A biological control agent Microctonus aethiopoides was released at Richmond and Rai Valley between August 2006 and March 2007 By May 2007 it was parasitising from 4 to 14 of S lepidus adults which indicates it is likely to become permanently established

Managing biological succession in intensive pastoral ecosystems for improved production and sustainability

Use of forage succession to increase productivity and upgrade runout pasture has become an integral part of modern pastoral production systems Use of new forage types has increased along with increases in area sown This growth in forage crop use and diversity has largely been without a coordinated view to long term benefits and costs in terms of weeds pests and diseases This paper describes the potential impacts on insects weeds and nematodes of a forage succession (pasture to turnips to annual ryegrass to turnips to perennial ryegrass/white clover) that commonly occurs in the Waikato region of New Zealand Pest distributions host ranges phenology and survival biology are used to elucidate strengths and weaknesses of the rotation Knowledge gaps are identified so that they can be addressed and add to robust forage succession design in the future

Colonisation of renovated pastures in Waikato by four coleopteran species

In autumn 1998 a farm scale replicated field trial was established in Waikato New Zealand to measure the productivity of combinations of old and new ryegrass and white clover cultivars Colonisation in the first two years of the trial by Costelytra zealandica Heteronychus arator Naupactus leucoloma and Sitona lepidus was monitored By the end of winter 2000 no difference in densities of any of the pest species monitored could be attributed to cultivar treatments However dispersal behaviour and soil type did have a significant effect on pest densities Naupactus leucoloma which disperses by walking was found in greatest densities on the edges of the trial Costelytra zealandica which disperses by flying was initially aggregated in paddocks with shelterbelts Heavy infestations of H arator which also disperses by flying were associated with good soil drainage Sitona lepidus which disperses by flying was evenly distributed across the trial

The behaviour of adult Sitona lepidus Gyllenhal (Coleoptera Curculionidae) in response to white clover

Individual adult Sitona lepidus were given the choice between damaged or undamaged seedlings mature plants of white clover damp soil or a blank in laboratory experiments carried out in a simple olfactometer Adult weevils displayed five different behavioural responses two of which head lifting and antennal movement appeared to be associated with host location In choice tests 7484 of adults chose a white clover plant over the blank or damp soil When given a choice 72 of adults selected white clover seedlings over mature plants Root and leaf damage did not affect response of S lepidus to white clover seedlings

Interaction between clover root weevil and clover root type

A slant board experiment investigated the effect of four white clover (Trifolium repens L) root types on tolerance of root feeding by larvae of clover root weevil (Sitona lepidus Gyllenhål) Root damage was determined by image analysis and larval weight gains were measured Differences in root type did not have a major impact on initial damage by clover root weevil However different root types were affected differently by the clover root weevil A clover genotype with long fine roots had more functional root length after larval feeding than genotypes with different root types

Effect of summer irrigation on population dynamics and reproductive status of adult Sitona lepidus in the Waikato

Populations of adult Sitona lepidus were sampled from five irrigated and five non-irrigated dairy pastures in the Waikato from November 1998 to April 1999. Under irrigated conditions, the presence of a second peak of adults with significantly more tenerals present provides evidence of a second generation over the summer months. The importance of the role of moisture in the development of S. lepidus was further demonstrated by the differences in the development of eggs in the calyces of sexually mature females. Egg development was significantly greater in females in irrigated pastures. Onset of rain after a dry period resulted in rapid egg development in females in non-irrigated pastures. These findings explain why the summer dry La Nina weather conditions in the Waikato led to farmer observations of a reduced impact of S. lepidus on clovers in Waikato pastures in 1998 and 1999.